Usually drum brakes are operated by a Bowden cable which extends via corresponding deflection means into the brake drum and/or the brake bowl. Details can be taken from page 135 of the Brake Handbook, 9th edition (Bartsch publishing house) or from FIGS. 4 and 5 and the pertinent description of EP-OS 309 079. Deflection of the Bowden cable as well as a corresponding seal entail difficulties. Therefore, one has proceeded to provide the actuating device with an actuating lever which projects through a corresponding aperture in the brake carrier into the brake drum. The end of the actuating lever disposed within the brake drum actuates the brake shoes, e.g. by way of an expanding lock (see the above-mentioned literature), while a Bowden cable makes catch at the end of the actuating lever disposed outside of the drum in the direction of trajectory motion.
In order to not impair the effect of the drum brake by the ingress of spray water, it has been suggested to seal the through hole where the brake lever passes through by providing a flat seal with a corresponding slot permitting the swing movement of the actuating lever. However, because of the lever's extension transversely to the direction of slot, the seal's slot is always somewhat open on both sides of the brake lever so that sufficient sealing of the brake drum vis-a-vis spray water is not safeguarded.